1. Field of the Invention
The present invention relates to a power supply apparatus.
2. Description of the Related Art
In an example of a supply apparatus for a vehicle-mounted device, a full-bridge inverter is provided on a primary side, and power of each of two different voltages is transmitted to a secondary side via a transformer (for example, see JP-A-2013-247814).
In the technique described in JP-A-2013-247814, a primary winding, a secondary winding, and a tertiary winding are wound in the transformer. The full-bridge inverter is connected to the primary winding, and hence the primary winding serves as part of the primary side of the transformer. On the other hand, the secondary winding and the tertiary winding serve as parts of the secondary side of the transformer.
More specifically, a first circuit includes a plurality of diodes, an inductor, and a capacitor, and is connected to the secondary winding. A second circuit includes a rectification circuit including a plurality of diodes and a plurality of semiconductor switching elements, and a step-down chopper circuit, and is connected to the tertiary winding.
The output voltage of the first circuit is controlled by a switching operation of the full-bridge inverter provided in the primary side, and the output voltage of the second circuit is controlled by a switching operation of the semiconductor switching elements of the rectification circuit which is connected to the tertiary winding. With this configuration, two different voltages are output at the same time using the single transformer.
The switching operation timing of the full-bridge inverter provided in the primary side and that of the semiconductor switching elements of the rectification circuit connected to the tertiary winding are controlled in outputting two different voltages at the same time using the single transformer, whereby the switching loss and surge voltages are lowered.